spacer back contents
ERCIM News No.49, April 2002


Realizing Trust through Smart Cards

by István Mezgár and Zoltán Kincses

Trust from users is a fundamental element in network-based services. Building blocks of trust are different security mechanisms. A smart card (SC) is a device that can integrate different security mechanisms in a handy form, but interoperability problems can decrease its wide usability. Software reconfiguration can be a way to overcome this problem. A project has been started at SZTAKI to develop an ontology-based reference architecture that supports SC reconfiguration.

Trust and confidence are essential for the users of networked systems, as for all members of the Information Society. The lack of trustworthy security services is the main reason of not using the electronic and mobile technologies in private, business or in public services.

The basic term of trust means reliability in some person or thing, or to allow to do something without fear of the outcome. Trust is of different categories, eg, Impersonal/Structural trust, Dispositional trust, Personal /Interpersonal trust.

In order to motivate individuals to use a certain information system, users have to be convinced that it is safe to use the system, their data will not be modified, lost, used in other way as defined previously, etc. In case the individual has been convinced, one will trust the system and will use it.

Access control (identification), authentication, privacy, and confidentiality are services forming the sense of trust for a human being. To achieve these services three basic building blocks of security mechanisms are applied: encryption (for providing confidentiality, authentication and integrity protection), digital signatures (for authentication, integrity protection and non-repudiation), checksums/hash algorithms (for integrity protection and authentication).

Smart cards can become essential trust elements in a security infrastructure as they are able to integrate different security mechanisms besides the current application. They are efficient devices to execute security functions, such as digital signatures. The workable interoperability of technical and organizational frameworks and supporting infrastructures is a big problem, as the lack of them can decrease SC usability. Overcoming this problem can help the software reconfiguration.

In the close future smart cards will have a role more important than today. Multi-functional cards can integrate different applications; identity card, bank-card, health card, etc. They can be a key component for mobile phones used as mobile personal terminals, a personal trusted device (PTD).

The very broad field covered by the different applications needs different solutions for the expected functions of SCs. The way of identification (able-bodied, or handicapped), the different encrypting algorithms (strong/weak encryption) need different HW and SW solutions/configurations of the SC. The set of applications of a smart card can alter during its life cycle, so the SW configuration has to be modified. In these cases applications have to be added or removed, namely, the software of the smart card has to be reconfigured probably several times. Another demand is to have standardized interfaces to handle the different application software (interoperability), and standardized HW building blocks.

A balanced system means that the needed functions of the current application are realized with the optimal HW and SW. Optimal means to select the proper technical parameters with a combination of an economic financial solution. This demand needs a complex, flexible configuration that can be altered/modified according to the user's actual needs (eg geographic spot, new services). Defining this configuration is a real complex task, consequently, there is a need for a kind of structured description of the present (and possible future) requirements of the different applications, and of the HW and SW possibilities. This representation structure can be a reference architecture that is based theoretically.

The development of the reference architecture is going on in the frame of the project 'The Theoretical Elaboration and Prototype Implementation of a General Reference Architecture for Smart Cards (GRASC)', supported by the Hungarian Scientific Research Found (OTKA). The basic goal of the project is to produce a first qualitative version of a theoretical-based multi-view, multi-layer, multi-element description of SC functions, SW and HW systems and applications. This representation will be integrated, unified, consistent, and - very important- dynamic, as it will also describe the connections among the elements.
The starting point of research was to develop a smart card ontology (SCO). Smart card ontology, this special structured representation is the guarantee for the full description of entities (applications and system elements), their levels and the logical connections between the levels and the entities. The main characteristics of smart card ontology are; the formalization level is structured informal/formal, the purpose of application is the interoperability among systems and it is domain ontology. As the description of SC ontology would well exceed the given extent of the paper, only a few elements of the SCO are introduced: meta-ontology (defines the basic terms of ontology), activities, functions, architectures and building blocks, applications, etc. There are further subgroups, numerous terms and definitions completing the ontology.

Based on the ontology, the number and content of the dimensions of the reference architecture (RA) can be defined. As a second step, discrete reference models (RM) can be allocated based on the RA. Based on the content of the RA sets of the reference models will be defined. It can be done based on the elements of the ontology taking the logical, functional and the derivative connections into consideration. Each RM is in a close, strict functional/logical contact with the neighbouring reference models. This results that the boundary communication between the RMs and the logic (I/O dataflow) of this communication can be defined exactly. Based on this knowledge exact protocols can be determined.The figure shows a three-dimensional graphical representation of a function-application-realisation architecture with reference models (represented by cubes).

A three-dimensional graphical representation of a function - application - realisation architecture with reference models (represented by cubes).

A three-dimensional graphical representation of a function - application - realisation architecture with reference models (represented by cubes).

The expected results of the GRASC are a structured description of smart card systems from different aspects, easy configuration/reconfiguration possibilities of SCs for different (multi) applications, and content/form of communication can be clearly described in case of different functions/applications.

Please contact:
István Mezgár, SZTAKI
Tel: +36 1 279 6141

Zoltán Kincses, SEARCH Laboratory, Budapest University of Technology and Economics